QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Northern Idaho

Yes. A magnitude 1.8 earthquake was recorded in Northern Idaho, at 12:10 pm PDT on 31 July 2023 (19:10 UTC), 5.5 km deep.

· 5.5 km deep · released about 17 lb of TNT

10 km30 km60 km120 km N Idaho County 38 kmClearwater County 61 kmLewis County 84 kmRavalli County 95 kmMineral County 108 kmNez Perce County 111 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
Idaho today
every earthquake in Idaho in the last 24 hours
Magnitude
M 1.8 (ml)
Depth
5.5 km below the surface
Felt
no reports yet
Nearest
Idaho County, 38 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1201 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 13 km (8 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 17 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 870,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 620,000× the energy of this one
  3. Around the size people start to feel M 3.0 55× the energy of this one
  4. This earthquake M 1.8 about 17 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km since 2016 was M 4.1 on 2018-11-20 — about 2,500 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 46.1747, -115.3345. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Idaho County, ID 38 km (23 mi) SSW earthquakes near Idaho County
Clearwater County, ID 61 km (38 mi) NNW earthquakes near Clearwater County
Lewis County, ID 84 km (52 mi) W earthquakes near Lewis County
Ravalli County, MT 95 km (59 mi) E earthquakes near Ravalli County
Mineral County, MT 108 km (67 mi) N earthquakes near Mineral County
Nez Perce County, ID 111 km (69 mi) W earthquakes near Nez Perce County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

2 earthquakes have been recorded within 50 km since this one.

  1. 2.2 11 km SE of Weippe, Idaho
  2. 1.7 28 km ESE of Weippe, Idaho

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.